1. Field of the Invention
The present invention relates to a light quantity control apparatus.
2. Description of the Related Art
Conventionally, the light quantity control apparatus having the shutter mechanism and the light quantity adjustment mechanism includes the shutter blade that opens and closes the opening part for the exposure and the light quantity adjustment member that adjusts the quantity adjustment of the opening. And opening and closing of the shutter blade and the movement operation of the light quantity adjustment member are respectively processed by an individual electromagnetic drive source. Further, the shutter blade and the light quantity adjustment member are held at each position where the opening is opened and closed in the non-energized state to each drive source.
However, there are problems that the apparatus costs higher, enlarges and becomes heavy weight, and a consumed power increases since the conventional light quantity control apparatus includes each electromagnetic drive source as a driving source who drives the shutter blade and the light quantity adjustment member.
Then, Japanese Patent Laid-Open No. 2007-212645 proposes the light quantity control apparatus that operates the shutter blade and the light quantity adjustment member with one electromagnetic drive source. The stepping motor is driven at the three positions so as to drive the shutter blade at the three positions by the arm member fixed to the stepping motor, and the aperture blade is provided the allowance formed into the elongate hole so as to drive the shutter blade at the two positions by interlocking with the arm member. By this combination, it is possible to select transferring of the shutter blade into and from the opening part for the exposure or transferring of the aperture blade into and from the opening part for the exposure.
However, there is a problem that the light quantity of the opening part stops for a moment in the prior art disclosed in the Japanese Patent Laid-Open No. 2007-212645 since the shutter blade opens and closes when the aperture blade as the light quantity adjustment member operates opening and closing. Further, there is another problem that the shutter blade collides with the stopper and bounds when the shutter blade closes.